Tag Archives: greenhouse gases

Carbon sequestration and buckyballs (aka C60 or buckminsterfullerenes)

Sometime in the last few years I was asked about carbon sequestration (or carbon capture) and nanotechnology and had no answer for the question until now (drat!). A July 13, 2015 Rice University (Texas, US) news release (also on EurekAlert) describes some research into buckyballs and the possibility they could be used to confine greenhouse gases,

Rice University scientists are forging toward tunable carbon-capture materials with a new study that shows how chemical changes affect the abilities of enhanced buckyballs to confine greenhouse gases.

The lab of Rice chemist Andrew Barron found last year that carbon-60 molecules (aka buckyballs, discovered at Rice in the 1980s) gain the ability to sequester carbon dioxide when combined with a polymer known as polyethyleneimine (PEI).

Two critical questions – how and how well – are addressed in a new paper in the American Chemical Society journal Energy and Fuels.

The news release expands on the theme,

The amine-rich combination of C60 and PEI showed its potential in the previous study to capture emissions of carbon dioxide, a greenhouse gas, from such sources as industrial flue gases and natural-gas wells.

In the new study, the researchers found pyrolyzing the material – heating it in an oxygen-free environment – changes its chemical composition in ways that may someday be used to tune what the scientists call PEI-C60 for specific carbon-capture applications.

“One of the things we wanted to see is at what point, chemically, it converts from being something that absorbed best at high temperature to something that absorbed best at low temperature,” Barron said. “In other words, at what point does the chemistry change from one to the other?”

Lead author Enrico Andreoli pyrolyzed PEI-C60 in argon at various temperatures from 100 to 1,000 degrees Celsius (212 to 1,832 degrees Fahrenheit) and then evaluated each batch for carbon uptake.

He discovered the existence of a transition point at 200 C, a boundary between the material’s ability to soak in carbon dioxide through chemical means as opposed to physical absorption.

The material that was pyrolyzed at low temperatures became gooey and failed at pulling in carbon from high-temperature sources by chemical means. The opposite was true for PEI-C60 pyrolyzed at high heat. The now-porous, brittle material became better in low-temperature environments, physically soaking up carbon dioxide molecules.

At 200 C, they found the heat treatment breaks the polymer’s carbon-nitrogen bonds, leading to a drastic decrease in carbon capture by any means.

“One of the goals was to see if can we make this a little less gooey and still have chemical uptake, and the answer is, not really,” Barron said. “It flips from one process to the other. But this does give us a nice continuum of how to get from one to the other.”

Andreoli found that at its peak, untreated PEI-C60 absorbed more than a 10th of its weight in carbon dioxide at high temperatures (0.13 grams per gram of material at 90 C). Pyrolyzed PEI-C60 did nearly as well at low temperatures (0.12 grams at 25 C).

The researchers, with an eye on potential environmental benefits, continue to refine their process. “This has definitely pointed us in the right direction,” Barron said.

Here’s a link to and a citation for the paper,

Correlating Carbon Dioxide Capture and Chemical Changes in Pyrolyzed Polyethylenimine-C60 by Enrico Andreoli and Andrew R. Barron. Energy Fuels, Article ASAP DOI: 10.1021/acs.energyfuels.5b00778 Publication Date (Web): July 2, 2015

Copyright © 2015 American Chemical Society

This paper is behind a paywall.

Venezuela, oil production, and reducing its environmental footprint

The Nov. 14, 2012 article by Humberto Marquez for AlertNet; a Thompson Reuters Foundation Service, provides a context for why Venezuela is so interested in reducing the environmental footprint left by oil production,

Venezuela, a founding member of the Organisation of the Petroleum Exporting Countries (OPEC), extracts close to three million barrels of oil a day and has over two billion barrels of heavy crude oil reserves.

There are six refineries in the South American country that process a total of 1.1 million barrels daily.

Meanwhile, according to OPEC figures, the country consumes 742,000 barrels of different types of fuel daily, of which 300,000 barrels correspond to the gasoline used by more than six million motor vehicles.

The Ministry of the Environment reports that Venezuela is responsible for 0.48 percent of worldwide emissions of greenhouse gases and 0.56 percent of one of these “villains”, carbon dioxide.

Here are a few details about the research they are currently pursuing,

“We are seeking to use nanoparticles of metallic salts, such as iron, nickel or cobalt nitrates, as catalysts in oil-related processes that produce greenhouse gas emissions,” said Sarah Briceño, a researcher at the Centre for Physics at the Venezuelan Institute of Scientific Research (IVIC).

Catalysts are substances used to speed up chemical processes, “and our goal is to develop catalysts adapted to Venezuelan industry that will make it possible to reduce greenhouse gas emissions from activities such as oil refining and fuel consumption by motor vehicles by up to 50 percent,” Briceño told Tierramérica*.

Apparently, they are expecting this research to yield results in 2013 although it’s unclear whether that means laboratory results or practical applications. Interesting article and this is the first time I’ve found an opportunity to post about Venezuela and its nanotechnology efforts.